Modified Frailty Index for Patients Undergoing Surgery for Colorectal Cancer: Analysis of the National Inpatient Sample From 2015 to 2019

Background Frailty is increasingly recognized as a perioperative risk for numerous surgical diseases. We applied the modified frailty index (mFI-11) to the National Inpatient Sample (NIS) for patients undergoing surgery for colorectal cancer (CRC). Methods We performed a retrospective analysis of the NIS (2015-2019) including CRC patients undergoing surgery. We classified patients into frail (ie, mFI ≥0.27) and robust (ie, mFI <0.27) categories. Primary outcomes were in-hospital postoperative morbidity and mortality. The secondary outcomes included system-specific postoperative morbidity and length of stay (LOS). Multivariable regression models were fit. Results Within the 53,652 identified patients undergoing surgery for CRC, 19.1% were frail. Frail patients were at higher risk of postoperative mortality (3.1% vs 1.0%, odds ratio [OR] 1.96, 95% confidence intervals [CIs] 1.68-2.30, P < 0.001), morbidity (41.3 % vs 23.1%, OR 1.75, 95% CI 1.66-1.83, P < 0.001), and LOS (mean difference [MD] 1.46, 95% CI 0.29-1.62, P < 0.001). Significant differences existed between groups in system-specific postoperative morbidity, with the largest effect estimates seen in cardiovascular morbidities (OR 4.07, 95% CI 3.36-4.93, P = 0.001), followed by respiratory (OR 1.75, 95% CI 1.66-1.83, P = 0.001). Conclusion Frail patients undergoing CRC surgery are at risk of increased postoperative complications. Preoperative frailty screening may allow for individualized preoperative counseling.